Static printed material may be thought of as a form of read only memory which requires no power and stores its data in a form visible to the human eye. Vellum texts over a thousand years old survive to this day. Additionally, the data is presented generally in a format comfortable for human eye reading which presents printed text against a contrasting physical background of white or another contrasting colored paper. The physical nature of the printed material allows a user to physically sift through its data for “something of interest,” for example, by flipping through its pages and looking at illustrations or catchy titles in a magazine. One can hold one's place in a physical book, and flip back a clump of pages, which the user's brain knows is about the right section, to reread a section and look back at the place held by a finger too. Of course, physical books, periodicals and paper have their disadvantages too due to the permanent setting of information on their pages.